Turret traversing mechanism



March 9, 1948. v. E. MATULAITIS EI'AL 2,437,646

TURRET TRAVERSING MECHANISM 7 Filed Aug. 5, 1945 4 Sheets-Sheet l mm @W March 9, 1948. v. E. MATULAlTlS ETAL 2,437,646

TURRET TRAVERSING MECHANISM Filed Aug. 5, 1943 4 Sheets-Sheet 3 /2 /2' ATTORNEY v. E. MATULAITIS EI'AL 2,437,646 TURRET TRAVERSING MECHANiSM March 9, 1948.

Filed Aug. 5, 1945 4 Sheets-Sheet 4 Patented Mar. 9, 1948 TURRET TRAVERSMG MEG Application August 5, 1943, Serial No. 497,552

Claw-e (Cl. 192-2) This invention relates to a turret traversing and control mechanism, and it has particular reference to the provision of means whereby a gun platform, such as a tank turret, may be either rapidly or slowly rotated in either direction, and quickly stopped and held when the weapon is aligned with a target.

Heretofore,.the turrets of combat weapons such as tanks have been provided with means for traversing by hand, or with power means to accomplish the same purpose. When the mounting for a medium tank, containing a 75 mm. cannon and a heavy caliber machine gun is traversed constantly by hand, an additional physical strain is imposed on the gunner which seriously detracts from his efiectiveness. Recourse has heretofore been made therefore to power mechanisms relieving the gunner of constant manual operation, and providing him with an auxiliary or alternative method of bringing his weapons to bear on the target. One system heretofore proposed has been a hydraulic system, patterned, to some extent, after the systems heretofore utilized with naval ordnance. These have the advantage of permitting the gunner to arrest the motion quickly at any desired point. They also have the great disadvantages, for land warfare in which rapid sighting is often indicated, of not moving the turret in position as quickly as desired, and taking up too much space in a vehicle such as a tank. Attempts have also been made to employ electric drives for these turrets, but the systems heretofore proposed have been deficient in imposing too severe a drain on the electric batteries, and in developing low torques at low speeds, with consequent poor regulation under conditions of variable loading.

What is wanted is a control apparatus taking up the minimum possible space within the tank, permitting either rapid or slow traversing without attendant creep, and capable of either power or manual operation. The present invention contemplates the attainment of all these desiderata.

According to the present invention, there is provided a system of gearing which may be operated either manually, or from a power source such as an electric motor, and in either direction to the end that the turret may be swung to one side or the other of the body of the tank. As a matter of fact, the particular type of tank to which the present invention has been applied includes a turret which may be rotated 360, but it will be understood that the invention may also be utilized when the traversing range is limited. The gearing is provided with a manually operable handle by means of which the gunner may turn his piece either way, as slowly as he likes, or as rapidly as his strength permits. There is also provided a connection between the motor and the gearing so that the motor may also rotate the turret, and the speed control for the motor armature is regulated, so that the motor may revolve at a creeping speed, or at a very high speed enabling the turret to be spun around as much as ten or fifteen revolutions per minute. The motor regulatory system is such that the moving system may be arrested rapidly, and the manual and power inputs are interconnected through the gearing so that they may be operated separately or conjointly withoutinterference with each other.

The control of these means of actuation is given over primarily to the gunner, who sights as well as fires the cannon. However, means are also provided whereby the tank commander can himself operate the turret without the necessity of transmitting his orders to the gunner with attendant loss of time in getting on to the target under emergency conditions.

For a fuller understanding of the principles of the invention. and'the advantages to be derived from the practice thereof, reference may be made to the following description of a preferred embodiment illustrated in the accompanyingdrawings. wherein:

Fig. 1 is aview of a tank equipped with a cannon, the turret therefor being broken away to show the control instrumentalities;

Fig. 2 is a section through the control and operating mechanism:

Fig. 3 is a section on the line 33 of Fig. 2, showing a motor brake;

Fig. 3A is a section along the line 3A-3A of Fig. 3, taken to show details of the brake spreader;

Fig. 4 is a perspective of the gearing, associated parts being eliminated for purposes of clarity;

Fig. 5 is a perspective of the manual control shaft, clutch, and associated parts;

Figs. 6 and 7 are sections respectively taken on the lines B-6 and 1-! of Fig. 5;

Fig. 8 is another perspective of the manual control shaft assembly, partially broken away;

Fig. 9 is a perspective of a cup included in the manual control shaft assembly; and

Fig. 10 is a wiring diagram for the motor control circuits.

The invention is shown, in Fig. 1, as incorporated in a medium tank having track laying treads 20, an armored body 21, and a turret including a well 22 and head 23 which move togather as one piece. The turret carries a cannon and 23 or other ordnance which is elevated or depressed and fired by a gunner who may take his station on a seat 25. The entire turret is mounted for rotation in a horizontal plane by means of a fixed race ring 26 secured to the body 2|, a concentrically disposed inner ring 21 secured to the head 23, and interposed balls 28. The head 23 and ring 26 are so formed as to approach each other closely through a labyrinthal gap, to reduce bullet splash and exclude as much dirt as possible, as shown in Fig. 2. Rotation of the turret, and thereby the traversing of the gun 24, is effected through the intermeshing of an internal ring gear 29, formed on the fixed race ring 26, and a driving pinion 3| mounted within the head 23, and which projects through an opening 32 formed in the side wall of the well 22.

In order to rotate the gear 3|, and thereby the turret, there is provided, according to the present invention, a manual and power drive and control mechanism, designated by the letter C in Fig. 1, and shown in detail in the remaining views. This equipment appears in Fig. 1 to be behind the gunner's position, in fact it is located to one side, and has been illustrated in a different position simply to avoid obscure or additional views. The unit C comprises a housing or casing 33 mounted on the turret wall by suitable means such as bolts 33 (Fig. 2), and in which the pinion 3| is located. A crank handle 35 projects above the housing. and the gunner may rotate it in either direction to traverse under manual control. The housing 33 also contains an electric motor 36 to provide a'power drive for the pinion 3|, and the flow of electricity to the motor is controlled by a switch box 31 provided with an operating handle 38. The structure of the box 31, as such, is not of the essence of the present invention, except as hereinafter pointed out in connection with a discussion of the wiring diagram, Fig. 10.

Here, in onjunction with this introductory description, it will be sumcient to note that the gunner may revolve the handle 38 in either direction to turn the turret one way or the other. Electric connections from the switch 31 lead to a resistance box 39 and thence to the motor 36 through cables ii and 42. Additionally, the energization of the motor is subject to control by the tank commander whose post cannot be shown in Fig. 1. For such purpose. the box 39 is wired to a junction box 33 through a cable at, and the connections to the commander's control switch are taken through these elements.

As thus far described, it will be apparent that the gunner may traverse either manually, by means of the handle 35, or by power drive by manipulating the handle 38, while the tank commander may also govern turret operation by his switch which leads to the motor circuits.

In order to provide for both manual and power operation in either direction of rotation, there is provided a planetary gear systemhaving inputs from both the handle 35 and the motor 36, and an ultimate output through the pinion 3| which meshes with the fixed ring gear 29. Referring initially to Fig. 2, it will be seen that the housing 33 of Fig. 1 includes a depending barrel to which is fitted the field winding 52 of a direct current motor 36, whose armature 53 is rotatably mounted in bearings 54 and 55 carried by end pieces 56 and 61. The end piece 56 may also carry the brushes 68 for the commutator 59. Th upper end of the motor shaft 6| has keyed thereto the rotor members 62 and 63 of an eddy current brake, whose field winding 38 is mounted in the bore of the barrel 6|. The shaft 6| extends above the end piece Bl into a housing section 65, where it is formed with a splined section receiving a mechanical brake drum 66. The shaft 6| is here connected, by means of a splined coupling 61, to an extension shaft 6|a, rotatably mounted in suitable bearings'carried by an upper housing section 66.

As will be discussed in detail later, the current supplied to the motor 36 is so regulated as to cause rotation of the shafts 8| and 6|a in either direction and at varying speeds. The eddy current brake is employed in this connection to secure speed'control. The mechanical brake within the housing section 66 is provided to lock the motor shafts when the armature 53 is at rest, and the application or release of this brake may also be effected through the electric circuits.

The mechanical brake, which is of a known type, comprises shoes 68 adapted to be pressed against the inner wall of the drum 66. and coupled at adjacent ends through an adiustor 10, which is anchored to the upper wall 13 of the section 65, and an actuator H whose operating boss 12 extends through the wall 13. Application of the brake is effected by upward movement of the actuator l I, which carries with it a spreader 14, best shown in Fig. 3A. This piece is conical, and it engages the pins I6, formed with tapered slots 16, through rollers Tl. When the actuator II is pulled up, the tapered faces wedge the rollers between them, thus pushing the pins 15 outward to force the shoes 69 into engagement with the drum 66. When the spreader drops, the shoes are retracted by tension sprin s 18 which interconnect them, as shown in Fig. 3. The spreader is operated by a solenoid 8|, secured to a bracket on the housing section 68. and whose plunger 82 is normally extended by a compression spring 83. The solenoid plunger and the brake actuator are interconnected by a lever 84, pivoted to a bracket 66 mounted on the wall 13. When the solenoid is energized, the plunger 82 is pulled up, thereby depressing the spreader 14 to release the rollers 11, and permitting the shoes to be pulled in by the springs l6. When the solenoid is deenerglzed, the spring 33 forces the plunger 82 down to lift the spreader it, and thereby apply the brake.

The upper housing section 68, which rests on the wall 13 of the section 65, is formed with an internal vertical wall 86 which cooperates to seal the brake housing 65 and solenoid plunger from oil and dirt. The vertical wall 86 also carries the bearings for the extension shaft Bio, and additional bearings for an idler shaft 31 which is mounted parallel to the shaft Bla, as illustrated in Fig. 2. The shaft 6|a is provided with a pinion 88 keyed thereto, which meshes with an idler gear 89 mounted on the shaft 87. The gear 89 in turn meshes with the external teeth of a ring gear 9|. The apparatus, as thus far described, constitutes the power input for the planetary gearing system whose ultimate output is the pinion 3|, in mesh with the fixed ring gear 29. From the discussion to this point. it will be understood that the shaft 6 la may be rotated in either direction, thereby imparting a like rotation to the ring gear 9|, or, the shaft 6|a may be looked through the mechanical brake, thereby holding the ring gear stationary.

As viewed in Fig. 2, the brake housing 65 is formed at its right hand side with an additional housing section 93 in which is disposed a mountthe ring gear 9| (Figs. 2 and ing and braking assembly for a shaft 95, whose upper end is provided 'witha lever 90 to which is or otherwise integrally connected thereto. The lower portion 93 of the sleeve member 99 is of increased diameter, and its outer surface carries a bushing upon which is mounted the hub 99 of The portion 98 similarly is bushed to receive a gear hub IBI having a spider carrying three planet gears I92 meshing with internal teeth formed on the ring gear SI and with the teeth of the sun gear 91. The upper end of thehub IOI is formed with a pinion I03, which meshes with a gear "ll-mounted on a shaft I95 which carries the driving pinion 3|. The assembly including the shaft 95, sleeves 96 and 99, and associated parts, is mounted in the housing portion 93 on a step bearing I93 and also in a cover plate I91 overlying the gear housing section 68. I

Referring particularly to Fig. 2, it will be noticed that the shaft I05 is formed as an elongated V enough tension is applied to the bolt I I3 to couple the gear I09 to the gear 3I through a load limit clutch. This is desirable, because sometimes the barrel of the gun 29 might strikean obstruction when being traversed, and the gearing should therefore, be permitted to slip to preclude serious damage to the gun or its operation mechanism.

Before describing in detail the mechanism entering into the assembly for the shaft 95 and its associated parts, reference may be made to Fig. 4, in which the gear train is shown without all of the attendant parts. Assuming that the manually operated shaft 95 is locked against rotation, then the gear 3i may be driven through the following train: from the shaft 9m and gear 88 through the idler 89, into the external teeth of the ring gear 9I, thereby causing the ring gear to rotate, and to carry with it the planetary gears I02, thus rotating the hub Ill! and pinion I 93. The drive is then through the clutched gear I9 5,

} into shaft I95 and pinion 3i, whose rotation I causes the turret to revolve within the race 29 by engagement with the teeth of the ring gear 29. It will be noted that this is a reversible drive.

Next assuming that the motor 33 is de-energized, and that the brake shoes 69 are extended to lock the shafts 3| and -BIa, it will be seen that the ring gear 9i is also'secured against rotation and becomes a fixed gear. Through the means hereinafter described, the shaft 95 isthen coupled to the sun gear 91, and rotation of the handle 35 therefore causes the sun gear to revolve, and to carry the planet gears I92 with it in engagement with the internal teeth of the ring gear 9|. This motion causes a rotation of the hub IDI and pinion I93, and thereby drives the pinion 3i through the same train previously described. It will be'noted that this gearing may also be operated in either rotational direction.

If the gunner should beoperating the handle 35 and if, at the same time, the motor 36 should also be started, then the turret will be revolved in that direction indicated by the relative speeds of 6 power and manual input, differentiation occurring in the usual fashion through the planetary gear system, It will accordingly be seen that both inputs may be operated simultaneously, and in the same or in opposite directions of rotation, without interference or binding in the gearing.

Referring now to Figs. 5 to 9 inclusive, thereis illustrated the means whereby the shaft 95 may ,be connected to or disconnected from the sun \gear 91, and the shaft may also be locked automatically when the power drive is utilized in preference to the manual drive. This assembly includes a type of clutch sometimes called a wind-up spring clutch, which has heretofore been used to provide a ratchet or overrunning connection between two parts. The simple wind-up spring clutch is, however, usuallythought of as permitting motion in one direction, but not the opposite direction, whereas in the inst-ant case. it is desired to provide motion in both directions, and with a dual input of power; Accordingly, a more extensive arrangement must be provided.

The manually rotatable shaft 95 is provided, within the well pontion 93, with a cup I2I having a reduced end I22 which is secured to the shaft 95 by means of a pin I23 inserted through a hole I24. The cup is formed with a narrow slot I25 and with a wide slot I26, the center lines of these slots lying in substantially the same diameter. Mounted within the cup I2I is an internal brake piece, best shown in Fig. 8, and designated by the reference numeral I28. .This piece is formed with a key I29 which fits into the slot I25 with considerable clearance, and a diametrically opposed key I3I having a reduced portion I32 which is located in the slot I28. The parts are so dimensioned that the reduced portion I32 is concentric with the outer surface of the cup NH. The piece I28 is also formed with an upwardly extending portion I33 adapted to fit within the bore 99 with a press fit, The hub members 98 and 96, together with the sun gear 91 are, as previously indicated, telescopically mounted on the shaft 95.

Encircling the outer Wall of the cup HI and engaging the reduced portion I32 of the key I3! is a flat coil spring I35 whose ends I33 and I3! abut the key I3I on opposite sides thereof. The normal clearance between the spring ends I31 and I36, with respect to the key I3I, is somewhat less than the clearance between the side faces of the key I29 and the side walls of'the slot I25. Hence, upon rotation of the cup I2I through the shaft 95, with respect to the piece I28, the key I3I will tend to engage one or the other of the spring ends I36 or I31 prior to contact between the key I 29 and the side walls of the slot I 25. The outer surface of the spring I35 fits freely within the bore of the housing 93.

Welded to the top and bottom convolutions of the spring I35 are inwardly extending ears I38 and I39 which are positioned in close proximity to the opposite side walls of the big slot I26. The normal clearance between the ears and the walls of the slot is slightly greater than the clearance provided for between the key I3I and the ends of the spring, but it is normally a little less than the clearance provided between the key I29 and the slot I25.

The hub piece 98 is formed with a flange portion I4I formed with diametrically opposed slots I42 and IE3 having a light press fit over the adjacent ends of the keys I29 and I3I. It will thus be understood that the cup I2I is rigidly secured to the shaft 95, the internal sleeve piece I28 is, through its extension I33, lightly press fitted into the bore of the hub section 88, and the slots I42 and I43 fit over the keys I28 and I8I. thereby coupling the pieces I28 and 88 together practically as an integral assembly. The coupling between the cup I 2I and the sleeve piece I28 and thereby the sun gear 91 is effected through the coil spring I35 and the way in which it engages with its associated members.

The functioning of the construction may best be understood by considering first the effect of rotating the shaft 95. This causes one side wall or the other of the big slot I26 on the cup I2I to engage, in the first instance, its associated spring ear I38 or I38. The thrust on the ear causes the spring I35 to wind up on itself and thus withdraw from holding engagement with the internal wall of the housing 93. At about the time that the spring is so wrapped up on itself, one wall of the slot I25 comes into contact with the adjacent side face of the key I28, and accordingly power is transmitted from the shaft 95 to the cup I2 I, and then into the internal piece I28 through the key connection I28. Any tendency of the internal piece and hub 88 to slip with respect to each other, is of course, forestalied by the key connection between the keys I29 and I3I and the slots I42 and I43. With the spring relieved, rotation of the shaft 85, therefore, causes rotation of the sun gear 81, and traversing of the turret through the gearing previously described.

Let it next be assumed that the shaft 95 is not manually actuated, but that the drive takes place through the motor 36. In this instance, there is a rotation of the gear 8i and planet gears I82, with a consequent reaction on the sun gear 81 tending to rotate it in one direction or the other. This causes an attempted rotation of the internal piece I28, and with it rotative effort on the key I3I as well as the key I29. Since the'normal clearance between the spring ends I36 and I31 and the key I 3I is less than the normal clearance existing at the ears I38 and I38, or adjacent the key I29, there is a thrust on the end of the spring, tending to unwind it. The spring therefore expands and, the harder the thrust, the greater the unwinding tendency. The convolutions of the spring I35 are, therefore, wedged against the internal hole of the housing 83, causing a binding effect and producing a braking action on the sleeve 88 and the sun gear 81.

If the gunner should rotate the handle 35 in either direction while the power is being applied, he will simply take up the few thousandths clearance or free play between the edges of the slot I26 and one or other of the ears I38 and I39. This will tend to wind up the spring and therefore release the sun gear 81. The gunner may, therefore, as a matter of pure mechanics, either operation is preferred. obviously. the braking system used for the sun gear 81 could also be applied for the motor shaft 8|, and a different type of brake could be applied to the sun gear driving system. The combination described is, however, quite advantageous for tank service, since it permits getting the parts into more compact form, and in an installation where space isat a pre- Consideration will next be given to the arrangement provided for controlling the speed of the motor 36, and thereby the traversing rate of the turret when operated by power. In the arrangement herein described, this control is eifected in part, by varying the current supplied to the armature circuit, and therefore the developed torque. While control of motor current for starting purposes is common enough, it is well understood that the series resistance starting control does not give good speed regulation. Nevertheless, we have discovered that by combining armature current control with excitation of an electrical or eddy current brake, good regulation can be achieved, 1

Referring again to Figs. 2 and 4, the pieces 62 and 63, which are the brake parts carried by the motor shaft 6i, are soft iron, each formed with a series of poles I5I whose end faces are slightly canted with respect to the shaft axis. These abut, through a few thousandths clearance, copper rods I52 laid in spaced slots formed in iron rings I53 and I54, the rings lying on either side of the coil 64," and the rods being interconnected along the faces of the rings, as indicated by the reference numeral I55. When current is supplied to the winding 64, and the motor is revolved, the flux emanating from the poles I5I rotates with the poles and thereby induces eddy currents in the stationary conductors I53 and their connectors I55. The action, which may be likened to that occurring in a short circuited generator, develops a torque resisting the rotation of the armature 53, and so Provides a braking force as long as the field winding 64 is energized. An excessive braking action, or locking of the poles I5I against the rings upon starting, is avoided by canting the poles so that as one edge is aligned with a segment between the conductors, the opposite edge is displaced therefrom.

Obviously, the driving force of the motor and the braking' forceof the eddy current brake may be modulated by varying the quantity of electricity supplied to each. In the present system,

add or subtract from the drive imparted by the motor, but the net result depends upon the relative speeds and directions of rotation. Normally, of course, the gunner would be too preoccupied, or at least disinclined, to engage in such tactics, but he is always free to do so. This therefore permits him to transfer immediately from power to manual drive, without bringing the system to rest or being called upon to shift any gears. It may also be noted that he is free at all times to place his controls in a neutral or non-driving position, and the system is then immediately arrested without tendency to creep.

It will thus be seen that there is a braking system provided for the motor to hold the ring gear 8| when manual actuation is desired, and another braking system for the sun gear 81 when power sistance is a network of parallel resistances,

rather than the customary series resistance of the usual starting box. With the network plan, the I currents may be supplied in suitable increments, but the amount of current carried by any branch can be limited, thereby safeguarding against arcing, and permitting the employment of small and easily actuated switches to cut in or disable any element of the circuit.

Further, we propose the introduction of the resistance for the brake coil circuit by taking, at least in part, the resistances used in the armature circuit, the degree of utilization being determined more complicated and expensive systems. With such type of control, the tendency of the motor to changespeed with a. change in external load is oilset by an automatic modulation of the braking action acting in the opposite sense. Thus, if the load increases to decrease motor speed, the

tendency toward speed reduction curtails thebraking current, thus maintaining the total torque substantially constant. If the motor speed tends to increase, the brake torque also tends to increase, thereby again restoring the system to balance. This provides for good speed regulation, and assures a smoothness in operation, and

elimination of creeping, which is very desirable in traversing mechanisms.

A wiring diagram for the control circuits of a tank turret motor and brake is shown in Fig. 10. Current is supplied from a 24-volt battery 13 to the motor armature 53 and field winding 52, as

well as the brake coil 84 and the solenoid 8| of the mechanical brake. The various resistances for the circuits are disposed in the box 39 of Fig. 1, while the circuit switches are located in the box 31 for actuation by the handle 38 in accordance with the drum controller plan of manipulation. The tank commander's control is included in Fig. 10 as that part within the dotted rectangle at the foot of the sheet. The system, as herein illustrated, contemplates the control of the motor speed as a substantially linear function of the armature voltage and a generally inverse diminution of the braking coil voltage drop. Having selected these actual rates. the values of the various resistances may then be chosen to proportion the increments of increase or decrease of current.

Referring to the diagram, it will be assumed that the switches are all in the positions shown, and that initialoperation will be through the gunners controller. The motor 38 is stopped, and the mechanical brake is set. To institute power operation, the gunner must first close master switch M, the other switch T in the battery line being a thermostatic switch which is normally closed. Initial movement of the controller handle 38 will first close either switches F, F, or R, R, conditioning the motor for operation in one rotative direction or the other, by excitation of the field 52 through either of these circuits:

For forward" rotation, from battery 3 and switches M and T into wires I8I and I52 to normally closed switch I83 in the commander's controller, through wires I 88 and I55 to switch F, and thence through wires I68 and I81 to the field winding 52 of the motor; returning via wires I88, switch F actuated simultaneously with switch F, wire I88 to normally closed switch I1I in the commander's controller. and thence via wire I12 to the ground and the opposite side of the battery.

For reverse rotation, from the battery to wire |88as before, thence via wire I13 to the contacts of switch R and through wire I18 into wire I88 and winding 52 to energize the field with opposite polarity; returning via wire I81 to the contacts of switch R, thence via wire I15 to wire I88, switch III, and ground. The initial operation of the controller thereby energizes the field for driving in one direction or the other.

Concurrent with the supply of current to the field 52, current flows through a coil C in parallel with the field, which is the energizing coil for a solenoid switch or contactor whose points are indicated at S Closing of the contactor S now energizes the solenoid coil 8i to release the mechanical shaft brake, the current flowing through wires I11, I18 and I18 to the solenoid 8i and thence to ground. The plunger 18 (Fig. 2) is thereupon depressed, and the brake shoes 89 disengage under the influence of the springs 18.

A limited amount of current Is also supplied to the armature 53 of the motor, the starting resistance being provided by the parallel and series resistance included in the following network: from the wire I18 into resistance marked I8I, thence through the closed contacts of switches marked I8, 9, 8, and 6 into series resistances I82, I83, and I84, then through wires I85, I88, I81 and I88 to the armature 53, and via wire I89 to ground and return. Simultaneously, through the two similar branches having resistances I3l and I92, which are coupled between the wires I18 and I81. The current admitted through these circuits is enough to drive the motor at a slow speed, without danger of burning the windings even though no appreciable back F. is generated.

Further movement of the controller handle 38 will cause the successive closing of switches Nos. 2 and 3, thus adding the resistances I83 and I94 in parallel with the initial resistances, and accordingly adding to the armature current and thereby the torque developed to overcome the mechanical and electrical braking load imposed on the motor shaft.

The closing of the contactor S also energizes the coil 68 for the eddy current brake by a direct, or full voltage circuit taken as follows: from wire I11 through wire I96 and the closed contacts of switch No. 4 into wire I91, thence via wire I98 to the contacts of switch No. 13, to No. 14 through jumper I99, to No. 15 througl. jumper 28I, and then'via wire 282 to coil 88. The return is taken through wire 283 and contacts oi switch 284 to the ground. Maximum excitation therefore generates the maximum flux tending to hold back the motor shaft, and accordingly the armature 53 will rotate at a very slow speed, and quickly come to rest if the controller is returned to a neutral position. I

When the controller handle 88 is moved to its next advancing position. switch No. 4 is moved from the position shown, thereby opening the brake circuit taken through wires I88 and I91, but establishing a new brake circuit as follows: from wire I18 through resistance WI and contacts of switches 10 to 6 inclusive into wire 288, thence into wires 281 and I81 to complete the circuit previously traced. It will be noted that the brake coil resistance is the resistance I8I, which is also an element of the armature network. Simultaneously, some of the armature current, formerly supplied through resistances I8I, I82, I83, and I88 in series, .is low bled off from the wires I85, I88, and I81, due to the Junetion of the wire 288 with the resistances I8I and I82. While the armature current undergoes negligible change consequently to this operation, the brake current is materially. reduced, and speed regulation by the interdependence of the armature and brake circuits, as previously set forth, now begins to have its eflect.

The next controller position closes switch No.

5, thereby short circuiting resistance I82. This change again does not appreciably alter the armature current. but it does not decrease the brake current by decreasing the voltage applied to conductor 288. The throwing of double pole switch No. 6 eil'ects two changes. one is to add resistance 289. heretofore by-passed through switch No. 6, to resistance I8 I. thus increasing the brake line resistance. The resistance 288 is also added in series to the armature network path extending from resistance I8I' through I84. a change which, taken alone. would tend to offset the closin of switch No. 5. However. switch No. 6. in its alternative position. introduces resistance 2II to the armature network. the new branch bridging wires I18 and I88 to admit more current to the wire I 81.

Switches Nos. 7 and 8. next actuated by the controller, repeat the step-by-step changes effected by movement of switches Nos. 5 and 6 respectively. Switch No. 8 introduces resistance 2I2 in series with the brake field 84 and also introduces resistance 2I3 as a new branch for the armature network. Switches Nos. 9 and 10 provide for further incremental changes in the brake circuit resistance by placing resistances 2I8 and 2I5 in series with resistance I 8| and the wire 288. They also add new branches to the network by introducing resistances 2 I 8 and 2 IT.

A further branch is added to the armature network by closing switch No. 11 to introduce re-.

sistance 2I8. The closing of switch No. 12 eliminates resistance I84 from the network branch extending from resistance I8I to wire I85. With the resistance I84 in, this branch has the maximum ohmic value. Additional branches for the armature network are added by the throwing of switches I3 and I8. which admit current through resistances 2H! and 22I. The conductance of the armature network is now very close to its maximum value. corresponding to an approach to max mum motor speed.

When the switches I3 and I4 are thrown. it will be noted that they successively open the path to the brake coil 84, heretofore taken through jumpers I89 and MI, and cause the brake circuit to flow through series resistances 222 and'223 respectively. The resistance in the brake energizing circuit is now at a maximum, and therefore, the impressed brake voltage has been brought close to its minimum value. It will have been observed. therefore. that as the various switches have been successively actuated. armature current has increased, while braking. efiort has decreased.

When switch No. 15 is thrown to its alternative position. the following events occur: The exciting circuit for the brake is broken, since wire 282 is disconnected from resistance 223, thus opening the circuit, and reducing the braking eifect to whatever may attach to the residual magnetism. The armature circuit wire I8! is connected to ground through coil C thereby energizing this coil to close a contactor whose points are designated S Closing of these points directly connects wires I18 and I81 through wire 224, thereby admitting the maximum current to the armature 53. It may be noted that the coil 0 is of the type requiring a predetermined minimimi voltage for its operation, and if the controller handle 38 should be moved rapidly from neutral to the No. 15 position, switch S would not immediately close. but would be delayed until the armature had picked up some speed. The motor is, therefore, protected against a destructively excessive starting current.

It will be seen that the handle 38 may be swun back and forth in the same way as any manual controller handle to adjust the speed of the motor 38. If the gunner should desire to change direction suddenly, he simply reverses the controller handle, the electric braking action becom-- ing progressively greater as the neutral position is reached, and the mechanical brake engaging at the neutral point to arrest the movement of the turret.

If, at any time. the tank commander should elect to operate the traversing motor, he may do so by manipulating the switches in his controller. Switches I83 and HI are, as heretofore explained, interposed in the circuit for the motor field 52. Throwing of these switches to their alternative positions therefore interrupts the field current, de-energizes the coil C to open contactor S thereby opening the armature circuit, the energizing circuit for the eddy current brake,

and the solenoid 8| to apply the mechanical brake. If the motor is operating when these switches are thrown, the system is accordingly quickly brought to rest. Switch 284, interposed in thecircuit for the brake coil 84, may be set to throw in sequence to the movement of switches I83 and Ill, and, with it. a companion switch 228.

The movement of switch 284 interrupts the cir.. cult between the wire 203 and the ground, thereby precluding the re-establishment of the eddy current brake supply circuit. This movement also sets up a conditioning circuit for the armature 53 as follows: A wire 221, leading to a contactor solenoid C passes through switch 284 and wire 228 to ground. Energization of the coil C causes the closing of contactor switch S to establish a connection between wires I18 and I81 through a protective resistance 228, thereby providing for flow of current to themotor armature when the contactor S is again closed. At the same time, the movement of switch 228 establishes a shunt circuit through the coil C by flow from wire I81 into coil 0*, thence through wire 23I, switch 228, and wire 228 to ground. When the voltage in this circuit is suificient to close switch S, a direct armature circuit through wire 224 will be re-established.

Switches FC and FC operate together to provide for forward motion, while switches RC and R0 are actuated together for reverse motion. Upon movement of switches FC and FC', 2. motor field circuit is established as follows: from wires I8I and I62 through switch I83 to wire 233, thence via wire 234 to wire I81 and field winding 52, returning through wire I88 to wire 235 to switch FC', and then via wire 238 to switch Ill and to ground through wire I12. The reversing circuit is from wire 233 to switch RC into wire 235 and thence to wire I88, returning through wire 234 to switch RC into wire 238 and to ground, via wires III and I12.

Either condition energizes coil C thus closing switch S releasing the mechanical brake, and permitting current to flow to the armature through resistance 229' and finally through wire 224. It will be noted that the eddy current brake is not brought into play by the commanders controller, nor does his control involve a large series of steps in admitting current to the armature. This is because the operation of the turret by the commander, at a remote post, is in the nature or an emergency action, he wants to get the guns laid toward the target as quickly as possible. Therefore the resistance interposed in his armature circuits is as small as it may be without incurring too great a risk of burning out the motor. It will be understood, however, that the commander's controller may be made to include a series of steps, if so desired.

While the invention has been described by ref erence to an embodiment thereof as adapted to a military tank, it will be obvious that it is not so limited, but that its principle may be utilized in many other relationships. It is also apparent that various'parts and sub-combinations may be utilized effectively without adoption of the whole, and that the nature of the invention admits of numerous modifications and variations without departure from its principles. The foregoing description should therefore be considered as illustrative, and not limiting, and it is intended that the scope of the invention should be deemed commensurate with the following claims,

We claim:

1. Traversing mechanism comprising a driving pinion, an electric motor having a shaft connected to the pinion, a mechanical brake for the shaft, an electrical brake for the shaft, means for supplying varying quantities of current to the motor to change the speed thereof, means operating as an incident to the initial energization of the motor to release the mechanical brake, means for supplying varying quantities of current to the electrical brake to change the retarding eifect thereof, said last named means being actuated to decrease the supply of current to the brake as the means for supplying current to the motor is actuated to increase the motor speed.

2. Traversing mechanism comprising a gearing housing and a driving pinion, a motor mounted on the housing and having a shaft operatively connected to the pinion through gearing in the housing. a mechanical brake for the motor shaft, means on the housing for operating the mechanical brake, an electrical brake having a shaft carried part and a stationary part, means for supplying electrical energy to the motor field and armature and to the electrical brake, and means for varying the energy supplied to said armature and electrical brake, said last named means including resistances so arranged that energy supplied to the brake is decreased as the energy supplied to the armature is increased.

3. In a traversing mechanism including a driving motor having a driving shaft, an electrical brake having a part carried by the shaft, a source of current for the motor and the brake, control means for progressively supplying increasing quantities of current to the motor and concurrently supplying decreasing quantities of current to the brake, a second control means, and means operative through the second control means for interrupting the supply of current through the first control means and directly establishing a supply circuit for the motor.

4. In a traversing mechanism including a driving motor, a motor shaft, an electrical brake having a shaft carried part and a fixed part, a source of current, a supp y circuit from the source to the motor armature, said armature supply circuit including a plurality of resistances connected in parallel, switch means in said supply circuit for introducing or disabling said resistances to vary the current supplied to the armature, a supply circuit for the electrical brake, said brake circuit including a resistance connected in series with the brake and source of current, switches for changing the value of the last named resistance and thereby the potential impressed on the brake, said last named supply circuit being interconnected with the armature circuit in such manner that part of said last named resistance is supplied by the parallel resistances of the armature circuit.

5. In a traversing mechanism, a driving motor, a motor shaft, a motor driven electrical brake having a shaft carried part and a. fixed part, a source of current, a supply circuit from the source to the motor armature including a network of parallel resistances, means for changing the value of said network and thereby the current supplied to the armature, a circuit for the electric brake from the supply source, means for connecting the brake circuit into the network, and means for selectively changing the point 01 connection between the brake circuit and the network thereby to vary the potential impressed on the brake, whereby variation in load affecting the speed of the motor produces a compensating change in the reaction of the brake driven by the motor.

VICTOR E. MA'I'ULAII'IS. TENO IAVEILI.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES EATENTS Number Name Date 873,312 Henderson'et a1. Dec. 10, 1907 1,175,346 Dearborn Mar. 14, 1916 1,452,221 Slider Apr. 17, 1923 1,611,963 Valentine Dec. 28, 1926 1,755,079 Schiebeler Apr. 15, 1930 1,793,228 Hackethal Feb. 17, 1931 1,804,457 Briggs May'12, 1931 1,830,003 Shailor Nov, 3, 1931 1,833,615 Myers Nov. 24, 1931 1,863,395 Connely June 14, 1932 1,996,365 Clinedinst Apr. 2. 1935 2,054,802 Bronander Sept. 22, 1936 2,151,176 Acker Mar. 21, 1939 2,214,807 Buckley Sept. 17. 1940 2,220,983 Waters Nov. 12, 1940 2,254,911 Riley sent. 2. 1941 2,294,786 Lear Sept. 1, 1942 

